Colored screening layer for sensitive photographic elements



, Aug. 8, 1933. M. w. SEYMOUR 1,921,545

COLORED SCREENING LAYER Fon SENSITIVE PHoToGE'APHIc ELEMENTS Filed oct. 29. 1931 me" nkoc:

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Patented ug. 8, '1933 UNITED STATI-:s rATENr OFFICE COLORED SCREENING LAYER FOR SENSI-- TIVE PHOTOGRAPHIC ELEMENTS-L Merrill W. Seymour, Rochester, N. Y'., assignor to Eastman Kodak Company, Rochester, N. Y., a Corporation of New York f .Application octobezs, 1931. sem1N0.571,941

7 Claims.

face or support side of a photographic element.

Heretofore such coatings have usually beenv made of a gelatin solution containing a plain dye or combination o1' dyes, or of some other colloid containing a dye or dyes, orvarious solutions of dyes in solvents. For many purposes, especially where the dyes are applied in a top`coat`ing, such screening layers should be non-diffusing, that is,

the dyes should not wander or bleed from one emulsion layer to another with which it is in contact.

I have discovered that colloidal suspensions of certain dyes, specifically the indo-phenols or certain dyes closely related to them, as disclosedv later in this specification, are particularly useful for this purpose and have to a marked degree the desirable qualities required. These may be made, for example, by mixing a gelatin solution of a nitroso derivative of a tertiary aromatic amine with a gelatin solution of a suitable phenolic substance in which the position para to the hydroxy group is not substituted. The resulting insoluble indo-phenol is precipitated in colloidal form in the gelatin. As a definite example, aA gelatin solution of p-nitroso dimethylaniline ismixed with a gelatin solution of alpha-naphthol, An insoluble blue dye, an indo-phenol, is formed'.

Alternatively, a gelatin solution containing a derivative of an aromatic diamine or amino phenol and a suitable phenolic substance may be oxidized with a stream of air. In place of phenolic substances, I may use compounds containing acid methylene groups, for example, 1-phenyl-3- methyl-S-pyrazolone. When such compounds are used, dyes relatedl to the indophenols are pro,- duced.

lOther colloids than gelatin may also be employed, as for example, gum arabic or starch. Gelatin is, however, preferable in most cases.

vThe following are some formulas for preparing '50 colloidal solutions of the type o! dyes described:

' EXAMPLE I p-Amino-diethynannine hydrochloride 2'.0 grams Water 200.0 cc.

'I'hymol 1.5 grams Ethyl alcohol, 95% 100.0 cc. 4 Gelatin, 12.5% solution 100.0k cc. Ammonia water., 28% dt--.. 3.0cc.

o Air is drawn `through this solution for several hours while the solution is kept warm. A deep blue color develops. The resulting solution is set to a jelly, shredded and washed in cold running Water and reheated for coating. This coating lmaterial may then be used as a blue iilter layer or as a non-halation layer.

EXAMPLE `II Solution A p-Nitroso-diethyl-anilinev 0.005 mole or 0.9 gram Ethyl alcohol, 95% con cc. Water 60.0 cc. Gelatin, 12.5% solution ;f.; 60.0 cc.

' Solution B- y Alpha naphthol 0.005 mole or 0.75 gram Ammonia Water, 28% 10.0 c. c. Water 120.0 c. c.

Ge1atin,12.5% solution 60.0 c. c.

Solution B is poured into Solution A and the mixture is heated to 120 F. It then turns to a deep blue color. The solution is set, shredded, washed, and re-melted, as for Example I.

A reddish-brown gel can be prepared by the use of 1-phenyl-3-methyl-5-pyrazolone and p-nitroso-diethyl-aniline. Other coatings of various colors are similarly made.

These dyes may all be easily removed from the films or plates by treating them with an alkaline solution oi sodium hydro-sulphite. Most of them may also be bleached by treatment in an acid bath. It is, of course, desirable -in nearly all Vcases that these dyes should be removed or l bleached during of after lthe development, nxing,

and washing or other chemical treatment to which the nlm is submitted. The type of coating I have described therefore, meets this requirement.

Coatings made according to my invention are especially useful where it is yimportant that the dye will not diiuse into another layer with which i lt is in contact, as, for example, in the case where two lms are rolled together face to face` asA contact, the picture exposure being made through the support side of the green sensitive nlm. 'Ihe green sensitive emulsion is given a thin top coat of agreen absorbingsubstance which prevents the green rays from aectingthe red .sensitive emulsion which has a'. certain sensitivity to green. This vgreen absorbing substance must' not diffuse into the greenr sensitiveA layer to any marked extent. It is for such e purpose that my invention is especially useful.

Non-diffusing color coatings of the type I have described. may also be used advantageously as non-halation layers in which case they are coated on the support side of the film or plate'. They 1 will be particularly useful in the case of films etteched drewing, the three figures oi which are siniiior perspective views of three diderent photographic sheets embodying my invention, the edges being much magnified to show the severel layers., i

The seine reference characters ere used in the severel gures to indicate leyers o identical or similar cherecter. l designates e support, pref erebly treiisperent, such es cellulosic :dim or glass, 2 designates e layer of photographic emulsion, end 3 design/sites o screening or enti-holo layer comprising e colloidal suspension or en indophenel dye or related dye. ln the drawing, Fig. l shows e.A screening layer coated over the photographic emulsion layer; Figure 2 shows the photographic emulsion lever coated over the screen ing loyer, end Figure s shows the photographic emulsion loyer end the screening or anti-halo 'loyer coated on opposite sides of the support.

E consider es included within my invention, all modifications end equivalents coming Within the scope of 'the appended claims.

What l claim as my invention and desire to be secured by Letters Potent of the United Stetes is:

l. A non-diffusing colored coating materiel ior -tise es e screening layer with sensitive photographic elements and comprising e protective coln loidai medium end a colloidal suspension ci en indophenol dye dispersed therein.

2. A non-diiusing colored coating materiel for use es a screening layer with sensitive `photo grophic elements and comprising a protective col loidel medium and a colloidal suspension of an indoplienol dye dispersed therein, seid dye heving the characteristics of being colored, non-diiiusing and easily bleached by immersion in o suitable bath.

3. A photographic element comprising e sup= port, e sensitive loyer, end o screening loyer comprising e, protective colloicl carrying in colloidal suspension e non-dusing indophenol dye.

i photographic element comprising e sup port, e sensitive loyer, end e screening loyer compricing a colloid carrying in suspension en indo phenol dye, the dye hoi/ing the characteristics that it is colored, does not diffuse in gelatine, end is reedily removable in e bieeching beth.

il. A photographic element comprising e sun port, e, sensitive lever, end e. screening loyer com- @rising protective coiloid carrying in colloidal susv pensieri' en indophenol dye, the dye having the characteristics that it is colored, docs not diffuse in gelatine, end is readily removable in o bieeciningjbeth, seid screening loyer being over the sensitive loyer.

o. e. photographic element comprising c support, e sensitive loyer, end e screening loyer cornprising a, colloidal suspension of en indo-phenol dye, the dye heving the characteristics that it is colored, does not diuse in gelatine, and is resdily removable in a bleaching both, said sensitive loyer being over the screening loyer.4

7. A photographic element comprising e suoi port, e. sensitive loyer, end e screening layer comprising e colloidal suspension of en indo=phenol dye, the dye having the characteristics tiret it is colored, does not diffuse in gelatine, end is readily removable in e bleaching bath, seid sensitive loyer and screening loyers being on opposite surieces or the support.

MERRLE.. W. SEYMGUR. 

